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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        var num =10
        num +=20
        console.log(num);//30
        num -=10
        console.log(num);//20
        num *=10
        console.log(num);//200
        num /=10
        console.log(num);//20
        num %=2
        console.log(num)//0
    </script>
</head>
<body>
    
</body>
</html>